When you create a new file from a template the new file doesn't store any information about the template so there's no straightforward way to get the template's path.

What you could do is add the path to the template as a CustomDocumentProperty of the template.

That can be done like this.
ThisWorkbook.CustomDocumentProperties.Add "TemplatePath", False, msoPropertyTypeString, ThisWorkbook.Path
In the new document you can then retrieve the path like this.
Dim strTempPath As String

    strTempPath = ThisWorkbook.CustomDocumentProperties("TemplatePath")
    MsgBox strTempPath